The answer is 400 but these websites on related links are good.
9000
10000000
100
It is 0 0.00005
e A number that has only 1 significant figure can't be rounded to 3 significant figures
Round 12 to 1 significant figure is 10.
7000
0.1
2,000,000
10000000
9000
It is 0.01
0.9
12
800
100
200